Road surface mixing device



Feb. 25, 1936. F, E AHERNE ROAD SURFACE MIXING DEVICE Filed Jan. 2, 1954 5 Sheets-$heet l mm Q MN MW F. E. AHERNE Feb, 125, 1936.

ROAD SURFACE MIXING DEVICE Filed Jan. 2, 1934 3 SheetsSheet 2 Feb. 25, 1936'. I F. E. AHERNE 2,031,628

ROAD SURFACE MIXING DEVICE Filed Jan. 2, 1954 3 Sheets-Sheet 3 .ZizdlW Patented Feb. 25, 1936 UNITED STATES FATENT OFFICE Claims.

This invention relates to a device for use in mixing surface material on road'beds and for that type of road machine moved along by external power, or its own, over a temporary track 5 laid on both sides of the road bed to mix the surface aggregate with binding material such as asphalt, tar, or the like.

The principal objects of the invention are to provide non-rotatable means for thoroughly mixing and turning over the stones, grave], or other surface aggregate, first in one direction and then in the other, as the machine moves along so that they will become thoroughly mixed with the liquid binding material and so that the surface will be shaped; to provide means whereby the said mixing means can be arranged to have the general effect of moving the stones or gravel back to substantiall their original position after they have been turned back and forth, by reason of the fact that the mixing means is located in alternate courses making respectively right and left angles; to provide a guide along each side of the mixing means for preventing the discharge or diversion of the aggregate outside the path of the machine along the road; to provide'means for elevating the center of the Whole mixing arrangement so as to leave a crowned roadway; to provide convenient gauges by which this adjustment can be observed and its extent noted; to provide means for holding the mixing arrangement in any position to which it may be adjusted; to provide convenient means for releasing the holding means for adjustment and. holding up of the lower parts preparatory to storage or relocation; to'provide the mixing arrangement itself in a separate unit from the frame; to provide an adjustable brushfor smoothing'the surface of the road; to provide means for bending these brushe s to conform to a .crowned road and to 40 provide a mixing element consisting of a flat metal strip twisted to enable it to perform some of the above mentioned objects.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which Fig. 1 is a plan of a complete road machine constructedin accordance with this invention;

Fig. 2 is a side view of a part of the same as indicated by the arrow 2 in Fig. 1;

Fig. 3 is a transverse sectional View taken on the line 33 of Fig 1;

Fig. 4 is a sectional view on the lineQ-Q of Fig. 3;

Fig. 5 is a plan of one of the mixing elements by itself;

Fig. 6 is a view like Fig. 3 showing a change in position to make a crowned roadway;

Fig. 7 is a rear elevation of the device showing the brush at the rear, and

Fig. 8 is a similar view showing the brush distorted for the crowned roadway.

The machine is shown with two side channel irons I0 constituting skids for supporting the whole structure and designed to be moved along a pair of forms or tracks, either temporary Wooden tracks along the sides of the roadway to be constructed or the surface of the aggregate which is prepared for shaping or mixing. These skids carry cross pieces II which are bolted at their bottoms to the channel irons and project upwardly so as to extend across the top from one channel iron to the other. These parts constitute the main frame of the device.

Carried by the cross pieces I I are bearings I2 for shafts I3 extending longitudinally of the frame. The side shafts I3 have links I4 keyed to them which, by horizontal links I5, are connected with a stud l6 carried by a lever l1 extending upwardly from the middle shaft I3 but not keyed to it. Fixed on a pair of longitudinal bars I8 carried by the frame II at the center are, in the form shown, semicircular racks I9, one for each frame 34, as will appear. Slidably mounted on each lever I1 is a pin 20 for engaging in the teeth of the rack and holding this lever and therefore the shafts I3, in any desired position. This pin is held in engagement with the teeth of the rack by a spring 2! and the pin is provided with a cord 22, or other connection, which] is connected with a horizontal rod 23 carrying a handle 24. The rod 23 passes through a slot 25 in the top of the lever H, which slot has its lowest portion at the center and diverges upwardly on both sides. When the handle 24 is pulled in either direction the rod 23 has to slide up the slot to ward one end thereof and it first pulls the pin 20 out of the rack. Then the lever H can be swung by this handle in the same direction to swing the links I4 and turn the shafts on whichl they are fixed. This action also turns the central shaft l3 because the stud I6 is secured to an arm 26 by a nut 39. This arm is keyed to the center shaft I3. for the stud I6 which permits the adjustment.

Eccentrics 39 are fixed to the shafts I3 and they are adapted to turn in their straps 3i which are fixed on arms 32. These arms are pivoted on studs 33 carried by a frame 34 located beneath The arm 26 has an arcuate slot 21 the frame. When these eccentrics are turned the portion of the machine to which the studs 33 are fixed will be raised or lowered. These frames 34 are shown as flexible for a purpose to be described. As the stud l6, when it is fixed by the nut 39, has to move with the pivot connections of the links I4 and IS, the whole frame 34 will be raised or lowered the same amount at all points. These frames 34 are raised to their highest limit when the device is to be stored or relocated. In this case the links are turned to the dotted line position in Fig. 1. The nut 39 can be loosened and the arm 26 turned to raise the center of the frame 34 for crowning, as shown in Fi 6.

There are a plurality of frames 34 shown in Fig. 2. Each unit of the mixing element comprises one frame 34 provided with a central portion 35. To each frame are secured a parallel series of fiat twisted metal mixing bars 36. They are twisted to bring their edges into a helical condition. These bars are secured by means of bolts 31 at their ends and it will be seen that they are set at an angle, that is, the centers of the several mixing bars are moved to one side of their ends so that the front portion of each bar is at an angle to the sides of the frame 34 and the other portion or other half is at the opposite angle. These frames 34 are inserted under the main frame crossways so that these mixing bars are located in a general longitudinal direction. A machine can be made with one or any desired number of these frames 34, two being shown. The pivot studs 33 above mentioned are mounted in bearings 38 carried by the frames 34 and therefore the raising of these studs will raise the frame. Each frame 34 is provided with a series of upwardly projecting vertical rods 40 which are scaled at 4| and show by reference to their position relative to the top of the frames H the elevation of the mixing bars 36. These rods pass through suitably shaped holes in the cross bars II and serve to hold the frames 34 to the frame H positively in a definite horizontal position.

The operation of the invention so far described is very simple. The surface aggregate, such as stone, gravel or combination thereof, is placed on the roadway in the usual manner. The machine is first used for smoothing and shaping up the surface aggregate close to the required contour. The bitumen or other binder is then applied to the surface of the aggregate. The machine is caused to pass over the surface carrying the mixing bars through the mass at a depth in accordance with the characteristics of the surface aggregate and the thickness of the mixture required. As each of these mixing bars moves forward, although it has no rotary action in itself, it induces a rotating and transverse reciprocating effect on the component particles comprising the aggregate. The aggregate particles disperse around, over and through the grooves and transversely to and fro within the angular spaces which characterize the mixing bars and their arrangement. Rotating over and over and imparted with a lateral motion by the forward half of the mixing bar and rotating back and returning laterally by the reverse action imparted by the second half, the particles composing the aggregate are deposited practically in their original position. In simple principle, the particles are rolled over and over first one way, then the other, producing a combined lateral reciprocating and circular motion completing a cycle by restoring the particles to practically their initial position. This causes a thorough and uniform coating of the binder on the component particles of the aggregate without disturbing the true contour of the surface. The machine is reversible and thus capable of operation in either direction, avoiding the necessity of the usual turning around and the consequent confusion and dishevelment in the surface contour. A

thorough mixing results without the actual displacement of the aggregate materially from the position in which it was originally placed during and after the trueing and shaping operation. The shape and true contour of the surface continue to improve during the mixing process, entirely eliminating the need for the usual regrading and reshaping operation.

The application of the term contour to the operating description of this device is further merited by an arrangement which permits the elevation of the central portion of the mixing and leveling units, whereby a crowned roadway with uniform surfacing depth is produced. If a crowned road is desired, the central eccentrics 30 are turned to raise the center of each frame 34 so that this frame assumes the position shown in Fig. 6. This is done by swinging the arms 26 by hand, after loosening the nuts 39. Consequently the mixing bars assume the position shown in that figure and a crowning of the road is provided. The scales 4| on the central gauge rods 40 indicate in relation to the side scales the amount of crowning.

In order to prevent the stones or gravel being piled up along the edge a lengthwise continuous guide 42 is provided partaking of the general zigzag shape of the mixing bars, that is, in outline. This guide is made sloping on its lower surface as shown in Fig. 1 and continues from one of the units 34 to the next one so that any stone or gravel that would normally be forced out and left in a longitudinal pile along the edge is forced inwardly by the fact that the guide 42 slants lengthwise toward and from the center parallel to the mixing bars. Thus this material is brought under the influence of the mixing bars at that side as it comes along so that this tendency to pile up along the edge is entirely eliminated. These guides 42 are bolted to the channel irons l0 preferably or otherwise fixed in position to permit any necessary adjustment.

In Figs. 7- and 8 is shown abrush 43 of wire or other comparative material having a flexible back 44 secured adjustably to the frame I l by means of bolts 45 and slots 46 through which the bolts pass. One of these brushes is placed at each end of the machine but the one brush is adjusted up out of operative position. The one at the other end is placed in operative position, as shown in Figs. '7 and 8, Fig. 7 showing it as arranged for a fiat road bed and Fig. 8 for a crowned one. The back 44 of the brush is sufficiently flexible to allow its center to be adjusted higher than its ends to secure this result.

The device may be pulled along by a draw bar 48 which is pivoted to eyes 49 carried by the end members of the frame II. Obviously these bars 48 are arranged to lie in a horizontal position on the machine when not in use.

It will be seen therefore that this is a comparatively simple construction and that the helical mixing bars, arranged in fixed. position on the machine, will have the effect of rolling the surface aggregate over first in one direction and then in the other to mix it thoroughly with the binder. This is an important feature because it gives a very efficient mixing action without providing any mechanism for rotating these bars, thus simplifying the machine and reducing the cost of manufacture and upkeep. The guides 42 prevent the deposit of a windrow of stones along each side.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. As an article of manufacture, a road machine having mixing bars consisting of helically twisted flat metal strips set at an acute angle to the direction of the motion of the machine.

2. As an article of manufacture, a road machine having helical mixing bars arranged substantially horizontally and arranged with parts at alternating angles to the direction of motion of the machine as it moves over a roadway.

3. As an article of manufacture, a road machine having mixing bars consisting of twisted fiat metal strips arranged in a substantially longitudinal manner, those near the center being adjustable upwardly to form a crowned road surface.

4. As an article of manufacture, a road machine comprising a main frame and a plurality of transverse units located under it, each unit having twisted metal mixing bars extending substantially in a longitudinal direction but at a slight angle thereto.

5. As an article of manufacture, a mixing unit for a road machine comprising a rectangular frame, and a series of twisted fiat mixing bars secured to said frame, said frame having a central member to which said bars are fixed at their centers at points to locate the centers of said bars out of line with their ends, whereby said bars slant in one direction on one side of the central members and in another direction on the other side.

6. As an article of manufacture, a road ma chine comprising a pair of longitudinal skids for supporting the entire structure, cross pieces secured to said skids extending upwardly and across from one skid to the other, and a plurality of units, each comprising twisted fiat mixing bars set at alternating slight angles to the direction of said skids, said cross pieces having rods by which the elevation of these units is indicated in definite relation to the main frame.

7. In a road machine, the combination of a main frame having means for guiding it along a roadway and supporting it, a unit transversely arranged under the said frame and comprising a separate frame provided with generally longitudinal but angularly arranged helical mixing bars at the bottom thereof, and guides carried by the main frame at the sides thereof to prevent piling up of road material at the edges of the drag.

8. In a road machine, the combination of a main frame having means for guiding it along a roadway and supporting it, a frame located under said frame and provided with generally longitudinal but angularly arranged twisted metal mixing bars at the bottom thereof, and guides carried by the main frame at the sides thereof, and extending continuously from one end to the other, said guides being of the same shape as the outline of said bars to prevent piling up of road material at the sides.

9. In a road machine, the combination of a pair of side skids for supporting the machine, a

frame secured to said skids and projecting above them, a series of twisted metal mixing bars arranged below the frame in non-rotating position with respect to said frame, a series of longitudinal shafts on the frame, means carried by said shafts for raising and lowering the mixing bars, and means for holding the shafts in their adjusted :positions.

10. In a road machine, the combination of a main frame, a plurality of longitudinal shafts carried thereby, a mixing bar frame beneath the first named frame, twisted metal mixing bars carried by the mixing bar frame, means carried by said shafts for supporting the mixing bar frame and raising and lowering it as the shafts are turned, a rack and pin for holding one of said shafts in fixed position, and means connecting all the shafts together so that when the first named shaft is held they will all be held in fixed position.

11. In a road machine, the combination of a main frame, a plurality of longitudinal shafts carried thereby, a mixing bar frame beneath the first named frame, twisted met-a1 mixing bars carried by the mixing bar frame, means carried by said shafts for supporting the mixing bar frame and raising and lowering it as the shafts are turned, a rack and pin for holding one of said shafts in fixed position, means connecting all the shafts together so that when the first named shaft is held they will all be held in fixed position, a pair of levers on one of which said pin is slidably mounted, said levers having upwardly diverging slots, a handle mounted in said slots and connected with the pin, whereby when the handle is pulled in either direction it will first rise in its slot and pull the pin out of the rack and thereafter serve as a means for swinging the lever.

12. In a road machine, the combination of a frame adapted to be moved along a roadway, a frame beneath the first frame, twisted metal mixing bars carried beneath the second frame and fixed thereto, vertical rods projecting up from the second frame provided with scales, the first frame having openings therethrough for guiding said rods indicating the elevation of the second frame by the said scales, and means whereby the second frame can be raised and lowered as a whole or its center raised more than its ends, for the purpose described.

13. In a road machine, the combination of a main frame adapted to be moved over the surface of a roadway, a second frame located underneath the first frame, twisted metal mixing bars carried by the second frame, an odd number of longitudinal shafts on the first frame, each shaft being provided with eccentrics, the eccentrics being fixed on their shafts, eccentric straps for the eccentrics pivotally connected with the frame below, whereby the lower frame can be raised by the turning of the eccentrics, links'keyed to the side shafts and extending upwardly from the side shafts, a link extending from the top of one of the first named links to the other and pivoted to both, a lever freely mounted on the central shaft and extending upwardly therefrom and pivotally connected with the last named link, and an arm fixed to the central shaft and extending upwardly therefrom and provided with an arcuate slot for receiving the pivotal connection of the lever with the last named link to permit said lever to swing and adjust its eccentric without adjusting the side eccentrics.

14. In a road. machine, the combination with a main frame, a flexible frame under it, stationary mixing bars carried by the second frame, means on the main frame whereby the second frame can be bent upwardly in the middle to provide for forming a crowned roadway,.a transverse flexible brush, and means for bending the brush to cause it to fit the surface of a crowned roadway.

15. The method of mixing road aggregate with a binder, in position in the roadway, and shaping the surface thereof; which consists in giving the mixture a rotary and transverse reciprocating motion in one direction in the roadway and then imparting to the mixture a second rotary motion and atransverse motion in the opposite direction to leave the particles composing the aggregate practically in. their original position.

FRANCIS E. AHERNE. 

